Recipe by Dreena Burton.
Preheat oven to 350°F (176°C).
In a bowl, combine the dry ingredients, sifting in the cocoa powder, potato starch flour, tapioca starch flour, baking powder, and xanthan gum, and stir until well combined.
In a separate bowl, combine the brown rice syrup with the vanilla and stir until well combined. (If the brown rice syrup is difficult to mix, try warming in a heat-proof dish in the toaster oven for a couple of minutes.) Then, stir in the canola oil, and add this wet mixture to the dry. Stir through until just well combined.
Place spoonfuls of the batter (about 1- 1½ tbsp in size) on a baking sheet lined with parchment paper. Bake for 11-12 minutes.
Remove from the oven, let cool on the pan for no longer than a minute, then remove with a spatula and transfer to a cooling rack.
Note: If using the orange zest, you can also add more orange flavor to these cookies using an orange-flavored dark chocolate bar. Instead of using chocolate chips, break or cut the bar into small morsels and mix into the batter in place of the chips.